Celebrity hairstyles often start trends, so I've been keeping an eye on the best and worst tressed at Fashion Week. At the Alice & Olivia party over the weekend, stars like Mena Suvari, Kelly Bensimon, Sophia Bush ,and Kelly Osbourne all showed up with vastly different hairstyles, and I've got the dirt on each:

First, I spotted Mena Suvari, who wore her hair in a teased, piled-high hairstyle swept to one side.

"How do you always come up with such different looks?" I asked.

"I just like to play," said Suvari, who once sported a shaved head as well. "I love being in New York because I have my team of people." Apparently, the West Coast is not the best coast for experimental hairstyles: "In L.A. everybody always does the same thing," she lamented. "My hairstylist works a lot in Paris," Suvari explained. "People always ask me if I do this myself and I'm like 'No!'"

Speaking of hair, I also spotted "One Tree Hill" star Sophia Bush, whose always shiny, always healthy hair has made me jealous for years. I asked the actress what she uses to take care of it.

"I'm a green nerd and I will admit it," Bush laughed. "This year as sort of a... New Year's resolution, not only in my house but with all of my girlfriends and my mom and all the women in my life, we went through and got rid of every product, everything that contains any chemical, any parabens. As far as hair, I started using all the David Babaii products 'cause they're sulfate and paraben-free, and it's amazing what a lack of chemicals does to your hair and skin." No kidding. She glows.

I also had to ask about Bush's gorgeous jewelry -- she had the most unusual, unique and delicate pieces.

"This is an old bangle from I think the '20s, the big ring is from Made Her Think, and I have a whole bunch of these little stackers from Fourteen Karats that I love."

And where, pray tell, does Bush shop for her great vintage jewelry?

"A really great vintage estate place in North Carolina where we shoot our show that no one knows about. Thus, I never reveal its name! Every time I go they have cool pieces in, so it's really fun." (pssst, North Carolina residents, if you think you know the shop she's talking about, leave a comment and let us know!)

Last up, I chatted with former Real Housewife of New York City Kelly Bensimon, a woman who always looks amazing. I asked Kelly to share some of her glam squad contacts, as years in the fashion industry must have connected her with some of the best:

"I live in New York, so I am exposed to some amazing hair and makeup people. One of my closest friends Bradley, he really basically does my hair almost 95% of the time. And then there's also Ric Pipino who I love, and Donald Mikula, I use him a lot -- he works with the Victoria's Secret girls."

That explain's Bensimon's perfect, voluminous waves. Lastly, I asked what her favorite hair color is, and whether her current shade was, ahem, natural:

"As a model I was blonde, I was red, I was auburn, I was so many different colors. You know now, I'm like, happy to be myself. This is my natural hair color."